The therapeutic use of carbon monoxide (CO) has recently been the focus of scientific interest, and the medicinal effects of CO have been analyzed in animal experiments. Fujita et al. pointed to a link between CO and prevention of ischemic injury in mice, “Paradoxical rescue from ischemic lung injury by inhaled carbon monoxide driven by depression of fibrinolysis”, Nature medicine, May 2001, 7, (5); p 598-604. Chapman et al. in “Carbon monoxide attenuates aeroallergen-induced inflammation in mice”, American Journal of Physiology, July 2001, 281; (1); pL209-16 further pointed to an immunoregulatory role of CO in aeroallergen induced inflammation in mice.
WO 98/13058 (Pinsky et al.) claims methods of treating ischemic disorders comprising administering to the subject carbon monoxide gas in a sufficient amount over a sufficient period of time. Animal experiments using rats treated with CO prior to lung harvesting and transplantation of the harvested lung are reported. However, the application fails to provide any useful information as to how CO may be safely and effectively administered to individuals suffering from ischemia in a manner that ensures that the individual benefits from such treatment without being at risk of suffering from CO intoxication.
Gas-supply systems for the treatment of patients with controlled doses of medical gases are known in the art. For example, European patent 0 621 051 discloses an apparatus for the monitored metering of nitric oxide (NO) into the respiratory air of a patient.
WO 98/31282, the disclosure of which is incorporated herein by reference, discloses a controlled gas-supply system, in which one or several gases are added to the respiration gas of a patient at varying proportions by means of a control device, which device may offer a program control, a sensor control, or a combined sensor/program control. However, the application is silent regarding the possibility to administer a carbon monoxide containing gas. Consequently, it fails to provide any guidance as to how CO may be safely and effectively administered to individuals while avoiding the risk of CO intoxication.
A method or an apparatus for administration of therapeutic amounts of CO to an individual, human or animal, is not known from the prior art. Furthermore, a method and an apparatus whereby carbon monoxide can be safely and effectively administered to an individual is not known.
It is therefore an object of the present invention to provide a method and an apparatus for the safe and effective administration of carbon monoxide to patients. It is a further object to provide a method and an apparatus for such administration which avoid the risks which follow from the toxicity of carbon monoxide in humans and animals. Another object of the invention is to provide a method and apparatus for the administration of carbon monoxide to patients whereby the gas is administered in an effective way to achieve the best possible therapeutic effect of the gas.
These and further objects are solved by the methods and apparatuses as herein described and claimed.